Apparatus for reading intelligence bearing characters



Aug. 4, 1970 D. H. sHEPARD ET AL 3,523,280

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' UH UH UJ LvL USC? LJ LvL 3 23 Us LU Ls 2 UH 2 -2-35 UJ Ls 4 w) .LJ Fig 45 United States Patent Oce 3,523,280 Patented Aug. 4, 1970 3,523,280 APPARATUS FOR READING INTELLIGENCE BEARING CHARACTERS David H. Shepard, Rye, N.Y., and Clyde C. Heasly, Jr., Arlington County, Howard W. Silsby, 3d, Annandale, and Pickard F. Bar-gh, Alexandria, Va., assignors to Farrington Electronics, Inc., Springfield, Va., a corporation of Massachusetts Filed Mar. 25, 1964, Ser. No. 355,149 Int. Cl. G06k 9/12, 9/13 U.S. Cl. S40-146.3 10 Claims The present invention relates in general to methods and apparatus for interpreting signals derived from scanning of intelligence-bearing items and activating selected ones of a variety of output devices in accordance with decisions made on the basis of selective information sensed from the items.

Briey, the invention relates to automatic interpretation of signals from scanning items of information such as printed characters, handwritten characters or any type of intelligence-bearing items by following the various streams or strokes of the intelligence-'bearing items and detecting by utilization of the signals the presence and/ or absence of preselected patterns to recognize the items and present `the recognition decision to an output device for recording and reproducing the intelligence-bearing item recognized. The following of the various streams or strokes of the intelligence-bearing items is accomplished by comparing on a time basis the recorded events occurring during a past scanning frame With those events ccurring during successive scanning frame intervals. By comparing time based events of past and present scanning frames it has been found that the various streams or strokes may be reidentiiied during each successive scanning frame to be followed to their natural end, during the course of which suitable logic circuitry has been developed to determine only certain preselected patterns unique within the intelligence-bearing items being scanned such as horizontal lines, slanted lines, vertical lines, joinings of the strokes or streams, splittings of the strokes or streams, etc., and to further determine within which stream or stroke, the preselected patterns are observed and as well as the relative positions of the streams or strokes within the intelligence-bearing item being scanned. Various combinations or permutations of occurrences and/or non-occurrences of such preselected patterns and/ or their positioning Within the character are selected, each set of such selected criterion to be peculiar to only one intelligence-bearing item in any group being scanned for identication purposes.

An object of the present invention is the provision of novel methods and apparatus for interpreting signals produced from scanning intelligence-bearing items, and by selected predetermined characteristics identifying each of the intelligenceabearing items in accordance with its representative yet distinct combinations or permutations of pattern characteristics which have been recognized from the scanned signals.

Another object of the present invention is the provision of novel reading apparatus for sensing and interpreting intelligence-bearing items by following their various strokes or streams to their natural ends and detecting certain selected predetermined intracharacter patterns by relating the various strokes or streams within the item for recognizing the intelligence-bearing item.

A further object of the present invention is to provide novel reading apparatus for distinguishing intelligencebearing items from unique patterns of portions thereof and reproducing the same, which is adapted to be selectively programmed to recognize a wide variety of intelligence-bearing items.

Another object of the present invention is the provision of novel reading apparatus for sensing and interpreting intelligence-bearing items upon following their various strokes or streams Ito their natural ends by comparing previous scanned item events with current scan item events, and fby utilization of the latter, detecting certain selected predetermined patterns for recognizing and reproducing the intelligence-bearing items.

A further object of the present invention is the provision of novel reading apparatus for sensing and interpreting signals produced from scanning intelligence-bear# ing items and by selected predetermined patterns, reproducing each of the intelligence-bearing items by having a programable interpreter apparatus adapted to recognize representative yet distinct combinations or permutations of patterns pertaining to the scanned items, which characteristics relate the various segments of an item to each other rather than to the scanning base and thus do not depend on alignment.

Other objects, advantages and capabilities of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing, showing only a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a block diagram of the present invention;

FIG. 2 is an optical schematic diagram of the optical scanning components of one form of scanning apparatus with which the present invention may be used;

FIG. 2A is an elevational view of the scanning disk in the scanning unit illustrated in FIG. 1, viewed from the line 2 2 of FIG. 1;

FIG. 3 represents Ia detailed schematic block diagram of the stream routing unit of the present invention;

FIG. 4 illustrates, by way of example, the manner in which the stream or strokes of a character are followed to identify the character illustrated;

FIG. 5 shows a series of time-related voltage wave forms showing time variant voltages at the corresponding points indicated alongside the wave forms;

FIG. 6 illustrates one form of delay apparatus which may be employed in the present invention;

FIG. 7 shows the detailed schematic diagram of the stream counter unit;

FIG. 8 illustrates a series of time-related voltage wave forms showing time variant voltages at the corresponding points indicated in the stream counter unit;

FIG. 9 shows the differentiating inverter stage circuit;

FIG. 10 shows the primer and special plate reset primer circuitry;

FIG. 1l is a detailed schematic diagram of the pattern record matrix unit;

FIG. 12 illustrates a series of time-related voltage wave forms showing time variant voltages at the corresponding points indicated in the pattern record matrix unit;

FIG. 13 is a detailed schematic diagram of the pattern control matrix unit;

FIG. 14 illustrates a series of time-related voltage wave forms showing time variant voltages at the corresponding points indicated in the pattern control matrix unit;

FIG. 15 is a recognition table showing the necessary criteria for recognizing the various characters in one embodiment of the present invention;

FIG. 16 shows one of the sets of the recognition criteria in the present embodiment necessary to enable an output AND gate for identifying a character recognized;

FIG. 17 is a schematic diagram of the vertical stream detector unit;

FIG. 18 shows the measuring unit and special measuring unit circuitry;

FIG. 19 illustrates a series of time-related voltage wave forms showing time variant voltages at the corresponding points indicated in the measuring unit and special measuring unit circuitry;

FIGS. 20, 22, 23 and 24 are used to illustrate the various character angles and configurations and their appearance to the vertical stream detector unit;

FIG. 21 illustrates a series of time-related voltage wave forms showing time variant voltages at the corresponding points indicated in the vertical stream-detector unit;

FIG. 25 illustrates, by way of example, the manner in which a stream split in a character is followed to be identified by the stream split detector;

FIG. 26 is a schematic diagram of the stream split detector and register unit;

FIG. 27 is a schematic diagram of the special reset circuitry;

FIG. 28 illustrates a series of time-related voltage wave forms showing time variant voltages at the corresponding points indicated in the special reset unit;

FIGS. 29 and 30 illustrate a series of time-related voltage wave forms showing time Variant voltages at the corresponding points indicated in the stream split detector unit during a split and no-split, respectively;

FIG. 31 is a schematic diagram of the stream position circuitry;

FIG. 32 illustrates a schematic diagram of upper stream and lower stream position indicator unit;

FIG. 33 is a schematic diagram of the stream join detector;

FIGS. 34 and 35 illustrate a series of time-related Voltage wave forms showing time variant voltages at the corresponding points indicated in the stream join detector unit during a join and no-join respectively;

FIG. 36 is a schematic diagram of upper join and lower join register and position indicator unit;

FIG. 37 is a schematic diagram of the stream horizontal detector unit;

FIG. 38 illustrates a timerelated voltage waveform showing time Variant voltages at the corresponding joints indicated in FIG. 37;

FIG. 39 is used to illustrate a character configuration and its appearance to the horizontal detector unit in FIG. 37;

FIG. 40 is a schematic diagram of the upper stream horizontal position indicator unit;

FIG. 41 is a schematic diagram of the end-of-character detector unit;

FIG. 42 is a schematic diagram of the end-of-character reset signals unit;

FIG. 43 illustrates a time-related voltage waveform showing time variant voltages at the corresponding points indicated in FIG. 42;

FIG. 44 is a schematic diagram of the split after join detector unit; and

FIG. 45 is a diagram indicating typical shapes to be detected for recognition of the different numerical characters.

GENERAL DESCRIPTION There is illustrated in FIG. 1 a functional block diagram of the present invention. This figure is intended, along .with the following description, to serve as an introduction to the detailed description which is presented hereafter. It will be observed that the exact number of interconnections between the several units as well as the reset circuit connections are disclosed in detail in the description which follows:

Documents 34 bearing intelligence information in character form are adapted to be fed from a feed mechanism 541 which may be similar to those described in co-pending U.S. patent applications Ser. No. 208,432 led July 9, 1962 by Howard W. Silsby et al., now Pat. No. 3,193,281 or Ser. No. 317,755 filed Oct. 21, 1963 by Walter Lee et al., now Pat No. 3,201,113. In the embodiment illustrated documents are fed one at a time past the scanner 542 where light is reflected from the surface of the moving document 34 to present at some focal point a moving image of the information which is progressively disected into elemental zones by a rotating mechanical slitted disk, appearing as discrete successive vertical slices of the information. The images are then converted into electrical signals by a photomultiplier tube in the video circuitry 543 producing signals which are a function of the intensity of the light energy received. The signals are amplified, clipped and then set to a controlled level thus providing a two level output signal denoting the presence or absence of a character portion, commonly termed recognition or non-recognition.

The recognition signal events during each scan frame are delayed for slightly less than one frame period and then stretched in the block unit 544. These signal events are then recalled for comparison with signal events of the next scan in unit 545. By such a comparison old streams or strokes of the character may be followed from scan frame to scan frame until the character ends, and new streams or strokes of the character may be recognized.

The comparison signal from unit 545 is then coupled to a stream routing unit 546 consisting of in the preferred embodiment a stream switching unit 547, a stream counter 548, a pattern record matrix 549 and a pattern control matrix 5'51, whereby newly observed streams are numbered in stream counter 548 and recorded along with old streams, according to the sequence in which the streams are recognized, in the pattern record matrix 549. This information is forwarded to the pattern control matrix 551 for controlling the switch circuity in stream switch unit 547 to regulate the actual orderly occurrence of the prenumbered streams as they are recognized during each successive scanning frame. The aforesaid developed signals are then applied to a detector 552 for producing pattern criteria for character recognition, comprising in the preferred embodiment a feature detector 553 and a position indicator unit 555 wherein the stream following is monitored to the extent that at least such patterns as streams splits, stream joins, vertical streams splitting after joins, and horizontal streams, may lbe detected in any one character being scanned. The splits and joins are associated with the streams in which they occur, and then the pattern of stream splits, joins and horizontals are observed by position indicator unit 555 so as to determine in which portion (lower or upper) of the character they occur so as to be located. The output of the recognition and criteria logic is then coupled to a series of output AND gates in the translator unit 556 which emits a signal representative of the recognized scanned character. From the video unit 543 signals are coupled to an end-of-character unit 557 determining the end of the character being scanned for developing reset and sampling signals Tf, TMI, Tpfz, and Tfd and a Tf unit 558 determining the end of each scanning frame for developing reset and sampling signals Tf, Tfn, Tf+2, and Tfd, whereby the aforesaid end-of-character and end-ofscanning-frame signals are employed throughout the logic heretofore described as will be shown in more detail hereinafter.

SCANNING APPARATUS An exemplary scanning assembly, which is one of several forms that could be used with the apparatus herein, is shown in FIG. 2 and corresponds fundamentally to that disclosed in U.S. Pat. No. 2,978,590 granted to D. H. Shepard. This scanning assembly, generally indicated by the reference character 31, is mounted directly over feed track 32 of a suitable automatic document feed mechanism so that the optical center axis of scanning unit 31 is perpendicular to the plane of the feed track with the optical center axis lying in the center of the scan zone from which information is to be read. The reading area is brightly illuminated by a pair of lamps 33. 

1. APPARATUS FOR READING INTELLIGENCE-BEARING CHARACTERS COMPRISING MEANS FOR SCANNING THE AREA OF A CHARACTER ALONG A PLURALITY OF SUCCESSIVE SCAN LINES PROGRESSING IN PARALLELISM ALONG THE CHARACTER AREA AND RECURRING AT A SELECTED REPETITION RATE, MEANS FOR SENSING THE INTERCEPTION OF EACH SCAN LINE BY THE CHARACTER DURING THE SCAN LINE AND PRODUCING INTERCEPTION AND NON-INTERCEPTION SCAN SIGNALS, RESPECTIVELY, DENOTING THE INTERCEPTION AND NONINTERCEPTION OF THE SCAN LINE BY A PORTION OF THE CHARACTER, MEANS FOR RECORDING THE SCAN SIGNALS PRODUCED DURING EACH SCAN LINE, DELAY MEANS FOR DELAYING THE SCAN SIGNALS FOR A PERIOD CORRESPONDING APPROXIMATELY TO SAID REPETITION RATE, SIGNAL STRETCHING MEANS FOR STRETCHING THE TIME DURATION OF SAID SCAN SIGNALS, MEANS FOR COMPARING ON A TIME BASIS DELAYED AND STRETCHED REPRESENTATIONS OF SCAN SIGNALS RECORDED DURING A PRIOR SCAN WITH SCAN SIGNALS PRODUCED DURING SUCCESSIVE SCAN LINES AND BY SUCH COMPARISONS CONTINUOUSLY FOLLOWING THROUGH SUCCESSIVE SCAN LINES CHARACTER CONFIGURATION STREAMS IN A CHARACTER BEING SCANNED FROM THE FIRST PORTIONS TO THE LAST PORTIONS OF SUCH STREAMS ENCOUNTERED BY THE SCAN LINES, COUNTER MEANS FOR 